In a 2007 study from the Netherlands, researchers found that men who drank coffee showed as much as 4.3 times lower incidence of cognitive decline than non-drinkers. The results showed reduced cognitive decline at all consumption levels compared with non-coffee drinkers - beginning with as little as one cup per day and increasing with additional consumption. The scientists found the maximum benefit was seen in those drinking three cups of coffee a day.

Two American studies in 2009 found that the equivalent of five cups of coffee a day improved problem-solving tasks and reduced brain levels of beta-amyloid plaques. Analyzing their findings, the researchers said that, “Long-term coffee intake could be a viable strategy for reducing the risk of Alzheimer’s disease, Parkinson’s disease, and other diseases associated with aging.”

Recent review studies, which survey the existing body of scientific literature, put these findings in a larger context. A 2013 study 1 stated that coffee consumption “may somewhat attenuate the rate of cognitive decline in women,” but that no correlation between amount and effect has yet been established. However, the review notes “mounting evidence” of a potential protective effect for coffee, tea, and caffeine.

Another 2013 review 2 notes that coffee and caffeine are known to enhance short-term memory and cognition and that there is limited research suggesting that long-term use may protect against cognitive decline or dementia.

Another 2014 review concluded that epidemiological and pre-clinical data also support their hypothesis that caffeine might not only be a cognitive enhancer, but also a disease modifier in Alzheimer’s disease.

While the source of the potential benefit is not certain, caffeine appears to be the likely candidate. However, research indicates that the protection may also come from coffee compounds such as magnesium and antioxidant compounds called phenolic acids.

Coffee and brain health continues to attract scientific attention, and new research will continue to emerge.